title: [Colorectal cancer].
abstract: OBJECTIVE
  To describe the multistep carcinogenesis of the colon and rectum, and updated in the screening diagnosis and treatment of colorectal cancer.
  
  
  BACKGROUND
  Colorectal cancer is one of the most frequent malignant neoplasia in developing countries. In Mexico, is the second malignant neoplasia of the gastrointestinal tract.
  
  
  METHODS
  A literature search was performed to known the usefulness of screening, diagnosis and treatment procedures. Also, some of our actual proceedings are described.
  
  
  RESULTS
  No impact in decreasing the mortality rate for colorectal cancer, has been observed with the contemporary screening programs in low risk population. The recommended treatment for colorectal cancer in early stages (Dukes A and B1) is the surgical resection alone. In those patients with colon metastasizing to the lymph nodes (Dukes C), a combination of surgery + chemotherapy is recommended. In patients with rectal cancer with full penetration until the perirectal fat or with lymph node metastasis (Dukes B2 and C) a combination of surgery, chemotherapy and radiotherapy is the elective treatment. Until today, is controversial if radiotherapy should be used pre- or postoperatively.
  
  
  CONCLUSIONS
  The colorectal carcinogenesis included a multistep where are involved a tumor suppressor genes and oncogenes. Surgery is the accepted treatment for early colorectal cancer. A combination of surgery + chemotherapy +/- radiotherapy is the elective treatment for locally advanced colorectal cancer.
authors.affiliation: Servicio de Colon y Recto, Hospital de Oncología, México D.F., México.
authors.forename: P
authors.initials: P
authors.lastname: Luna-Pérez
authors.forename: A
authors.initials: A
authors.lastname: Reyna Huelga
authors.forename: D F
authors.initials: DF
authors.lastname: Rodríguez Coria
authors.forename: R
authors.initials: R
authors.lastname: Medrano
authors.forename: J
authors.initials: J
authors.lastname: González Macouzet
mesh_terms: D000293:Adolescent; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002986:Clinical Trials as Topic; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000601:surgery / Q000628:therapy; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D011182:Postoperative Care; D011300:Preoperative Care; D011446:Prospective Studies; D012307:Risk Factors; D012812:Sigmoidoscopy; D013997:Time Factors
vernacular_title: Cáncer colorrectal.